
\thispagestyle{plain}
	\begin{quote}
	\begin{center}
	\begin{spacing}{2.5}
        %\raggedleft {\em To my parents Jianhua Xu, Min Zhang and my girlfriend Jing for their love and support. }
        \em{ To my parents Jianhua Xu, Min Zhang and my girlfriend Jing for their love and support. }
        \end{spacing}
        \end{center}
   	\end{quote}


